Keyboard with touch sensor and illumination

ABSTRACT

A keyboard may be provided that has keys overlapped by a touch sensor. The keyboard may have key sensor circuitry for monitoring switching in the keys for key press input. The keyboard may also have touch sensor circuitry such as capacitive touch sensor circuitry that monitors capacitive electrodes in the touch sensor for touch sensor input such as multitouch gesture input. The keyboard may include an outer layer of fabric that overlaps the keys. The fabric may have openings that are arranged to form alphanumeric characters. Light sources may emit light that passes through the openings and illuminates the alphanumeric characters. The touch sensor may have signal lines that are not visible through the openings. The signal lines may be transparent, may be covered by a diffuser, or may circumvent the openings so that they do not overlap.

This application is a continuation of U.S. patent application Ser. No.15/690,119, filed Aug. 29, 2017, which claims the benefit of provisionalpatent application No. 62/395,254, filed Sep. 15, 2016, which is herebyincorporated by reference herein in its entirety.

FIELD

This relates generally to electronic devices such as keyboards and, moreparticularly, to devices such as keyboards with touch sensorfunctionality.

BACKGROUND

Keyboards may be incorporated into laptop computers and may be used asaccessories for electronic devices such as tablet computers and otherdevices.

Some keyboards have trackpads to allow a user to supply touch input. Dueto space considerations and other constraints, it can be difficult orimpossible to provide desired touch sensor functionality to componentssuch as keyboards.

SUMMARY

A keyboard may have keys that are overlapped by a touch sensor. The keysmay be pressed by a user and the touch sensor may be used to supplytouch input.

Key sensor circuitry in the keyboard may be coupled to switches in thekeys using traces on a printed circuit or other substrate. The switchesmay be mounted to the substrate under movable key members. Duringoperation, the key sensor circuitry may monitor the switches todetermine when the keys are being pressed by the user.

The keyboard may also have touch sensor circuitry. The touch sensorcircuitry may be capacitive touch sensor circuitry that monitorscapacitive electrodes in the touch sensor for touch input from the user.

The keyboard may include an outer layer of fabric that overlaps thekeys. The fabric may have openings in the shapes of alphanumericcharacters. Light sources may emit light that passes through theopenings and illuminates the alphanumeric characters. The touch sensormay have signal lines that are not visible through the openings. Thesignal lines may be transparent, may be covered by a diffuser, or maycircumvent the openings so that they do not overlap.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an illustrative electronic device andassociated keyboards in accordance with an embodiment.

FIG. 2 is a perspective view of a portion of a keyboard in accordancewith an embodiment.

FIG. 3 is a cross-sectional side view of an illustrative key in akeyboard in accordance with an embodiment.

FIG. 4 is a top view of an illuminated structure such as a keyboard keyin accordance with an embodiment.

FIG. 5 is a circuit diagram of an illustrative keyboard with keys and anoverlapping grid of touch sensor electrodes in a capacitive touch sensorin accordance with an embodiment.

FIG. 6 is a top view of an illustrative fabric for a keyboard inaccordance with an embodiment.

FIG. 7 is a cross-sectional side view of an illustrative keyboard keythat is overlapped by a fabric touch sensor and an outer fabric layer inaccordance with an embodiment.

FIG. 8 is a cross-sectional side view of an illustrative keyboard keythat is overlapped by a fabric touch sensor, a diffuser, and an outerfabric layer in accordance with an embodiment.

FIG. 9 is a cross-sectional side view of an illustrative keyboard keythat is overlapped by a fabric touch sensor in accordance with anembodiment.

FIG. 10 is a diagram showing illustrative steps involved in formingtouch sensor signal lines on an outer fabric layer for a keyboard inaccordance with an embodiment.

FIG. 11 is a top view of an illustrative touch sensor fabric in whichtouch sensor signal lines circumvent an opening that forms analphanumeric character for a key in accordance with an embodiment.

FIG. 12 is a top view of an illustrative touch sensor fabric in whichtouch sensor signal lines are at least partially transparent inaccordance with an embodiment.

FIG. 13 is a cross-sectional side view of an illustrative keyboard keythat is overlapped by a touch sensor substrate and an outer fabric layerin accordance with an embodiment.

FIG. 14 is a top view of an illustrative touch sensor substrate in whichtouch sensor signal lines circumvent an opening that forms analphanumeric character for a key in accordance with an embodiment.

FIG. 15 is a top view of an illustrative touch sensor substrate in whichtouch sensor signal lines are formed from a metal mesh in accordancewith an embodiment.

FIG. 16 is a diagram showing illustrative steps involved in formingopenings through an outer fabric layer and a touch sensor layer inaccordance with an embodiment.

FIG. 17 is a top view of an illustrative touch sensor in which openingsare formed in touch sensor signal lines in accordance with anembodiment.

FIG. 18 is a cross-sectional side view of an illustrative keyboard inwhich light sources are interposed between a touch sensor and an outerfabric layer in accordance with an embodiment.

FIG. 19 is a cross-sectional side view of illustrative keyboard keysthat are overlapped by a touch sensor having transparent signal linesegments in rigid portions of the touch sensor and non-transparentsignal line segments in flexible portions of the touch sensor inaccordance with an embodiment.

FIG. 20 is a cross-sectional side view of an illustrative keyboard keyin which a light-reflecting wall surrounds a light source thatilluminates the key in accordance with an embodiment.

FIG. 21 is a cross-sectional side view of illustrative keyboard keys inwhich key members diffuse light to obscure touch sensor lines inaccordance with an embodiment.

DETAILED DESCRIPTION

A keyboard may be provided with keys to receive keypress input from auser and may be provided with overlapping touch sensor circuitry toreceive touch input from a user. An illustrative system of the type thatmay include keyboards is shown in FIG. 1. The system of FIG. 1 mayinclude an electronic device such as electronic device 10. Device 10 maybe an electronic device such as a laptop computer, a computer monitorcontaining an embedded computer, a tablet computer, a cellulartelephone, a media player, or other handheld or portable electronicdevice, a smaller device such as a wristwatch device, a pendant device,a headphone or earpiece device, a device embedded in eyeglasses or otherequipment worn on a user's head, or other wearable or miniature device,a television, a computer display that does not contain an embeddedcomputer, a gaming device, a navigation device, an embedded system suchas a system in which electronic device 10 is mounted in a kiosk, in anautomobile, airplane, or other vehicle, other electronic equipment, orequipment that implements the functionality of two or more of thesedevices. If desired, electronic device 10 may be a removable externalcase for electronic equipment or other device accessory, may be a strap,may be a wrist band or head band, may be a removable cover for a device,may be a case or bag that has straps or that has other structures toreceive and carry electronic equipment and other items, may be anecklace or arm band, may be a wallet, sleeve, pocket, or otherstructure into which electronic equipment or other items may beinserted, may be part of a chair, sofa, or other seating (e.g., cushionsor other seating structures), may be part of an item of clothing orother wearable item (e.g., a hat, belt, wrist band, headband, shirt,pants, shoes, etc.), or may be any other suitable device that includescircuitry.

Keyboards 12 may be used to gather input from a user. As shown in FIG.1, keyboards 12 may be incorporated into electronic devices such asdevice 10 or may be coupled to electronic devices such as device 10 viaa path such as path 14. Path 14 may be a wired or wireless path.Configurations in which device 10 includes an embedded keyboard 12 andis also coupled to a stand-alone external keyboard 12 by path 14 may beused, if desired.

FIG. 2 is a perspective view of a portion of keyboard 12. As shown inFIG. 2, keyboard 12 may have an array of keys 16. Keys 16 may be pressedby a user to supply keyboard 12 with keypress input (keypress events).Keys 16 may be alphanumeric keys, may be keys labeled with text (e.g.,“backspace,” “shift,” etc.), may serve as function keys, may includespecial-function keys (e.g., keys to alter the magnification ofon-screen content, keys for placing a device in a sleep mode, etc.), maybe single-function or multi-function buttons, may be alphanumeric keysarranged in a QWERTY format, may be arranged in rows and columns orother patterns, may be configured to form other types of keyboarddevices (e.g., numeric keypads, etc.), or may be any other suitablekeys.

A cross-sectional side view of an illustrative key in keyboard 12 isshown in FIG. 3. As shown in FIG. 3, a user's finger (finger 34) orother external object may be used to press down (inwardly) on key 16 indirection 20. Key 16 may have a movable key member such as movable keymember 24 (sometimes referred to as a key cap). When pressed indirection 20, key member 24 may move in direction 20 and may pressagainst and close switch 26 (e.g., a dome switch or other suitableswitch with open and closed states). In response to closing switch 26,keyboard control circuitry in keyboard 12 may detect a keypress eventand may supply the keypress information to control circuitry in device10. The keypress event may then be used as a control input for keyboard12 and/or device 10.

Springs or other biasing structures such as biasing structures 28 may beused to restore key 16 to its original undepressed state after pressurefrom finger 34 is released (i.e., biasing structures 28 may push keymember 24 upwards in direction 18 when a user lifts finger 34 off of key16). Biasing structures 28 may be formed from springy structures such asfoam, elastomeric polymer, spring metal, etc. If desired, biasingstructures 28 may be implemented using a scissor-shaped structure withsprings that support and bias key member 24 upwards. Other types ofstructures for supporting and biasing key members 24 for keys 16 may beused, if desired.

As shown in FIG. 3, keyboard 12 may have a housing such as housing 32.Housing 32 may be formed from one or more layers of material such asplastic, metal, fabric, and other materials. Keyboard substrate 30 maybe mounted within housing 32. Biasing structures 28 may be coupledbetween movable key members such as key member 24 and substrate 30and/or may be coupled between key member 24 and housing 32 or otherstructures in keyboard 12.

Keyboard substrate 30 may include signal traces 36 that allow controlcircuitry to communicate with keys 16 (e.g., traces that allow circuitryto monitor switches 26). Substrate 30 may be, for example, a printedcircuit (e.g., a flexible printed circuit formed from a sheet of polymerwith metal traces or a rigid printed circuit formed form a rigid printedcircuit board material such as fiberglass-filled epoxy). Switches 26 maybe mounted to substrate 30 (e.g., with solder, conductive adhesive,welds, etc.). Traces 36 on substrate 30 may be coupled between theswitch 26 of each key 16 and associated key sensor circuitry so that thecircuitry may detect keypress events (i.e., so that the circuitry candetermine which keys 16 have been depressed by monitoring which switches26 have been closed).

Key members 24 may be covered with one or more layers of plastic, metal,fabric, or other materials (see, e.g., illustrative layer 22). To helpensure that the shape of layer 22 conforms to the raised key shapes ofkeys 16, layer 22 may be debossed (embossed) in a die (e.g., a heateddie with key-shaped impressions that compresses layer 22 betweenopposing upper and lower structure into the shapes of keys 16). Laserprocessing techniques and/or other techniques may be used to formperforations and/or other openings in layer 22, may be used toselectively cut fibers, and/or may otherwise be used to process portionsof the material of layer 22 (e.g., to adjust key stiffness, keyboardappearance, and/or other attributes of keyboard 12).

Keyboard 12 may have light-transmitting regions that provideillumination for keys 16. For example, keyboard 12 may havelight-transmitting regions formed from openings 38 in layer 22 thatallow light 44 from light sources 40 to pass through layer 22 andthereby illuminate keys 16 for a user.

As shown in FIG. 3, a viewer such as viewer 94 may view keyboard 12 indirection 96. A light source such as light source 40 may be formed inthe interior of keyboard 12. Light source 40 may be formed from one ormore light-emitting diodes (e.g., organic light-emitting diodes,light-emitting diode dies formed from crystalline semiconductor, quantumdot light-emitting diodes, light-emitting diodes with phosphors, etc.)or may be formed from other light-emitting structures. With oneillustrative configuration, which may sometimes be described herein asan example, light sources for item 10 such as light source 40 may beformed from micro-light-emitting diodes (e.g., small crystallinelight-emitting diodes having dimensions of 100 microns or less, 200microns or less, 20-200 microns, more than 10 microns, less than 500microns, or other suitable size). Other types of light-emitting devices(e.g., lasers, electroluminescent panels, etc.) may be used in providingillumination for keyboard 12 if desired. The use of micro-light-emittingdiodes for forming light source(s) 40 is merely illustrative. Lightsources for item 10 may generate light at visible wavelengths, infraredwavelengths, and/or ultraviolet wavelengths (see, e.g., light 44 of FIG.3). If desired, luminescent material (e.g., phosphors formed fromphosphorescent materials, fluorescent dyes, a polymer or other materialcontaining quantum dots, etc.) may be used in converting light todesired wavelengths.

Layer 22 may have openings such as openings 38. Openings 38 may have theshape of an alphanumeric character or other symbol (glyph) or may haveany other suitable shape. As shown in FIG. 3, openings 38 (i.e., thesymbol, label, or other patterned structure formed from openings 38) maybe illuminated with illumination 44 (i.e., illumination 44 may serve asbacklight for an illuminated area formed from opening 38). Becauseopenings 38 may have a shape that forms a symbol or other desiredpattern, openings such as opening 38 of FIG. 3 may sometimes be referredto as patterned openings or illuminated regions.

Openings such as openings 38 of FIG. 3 may be formed by stamping(punching), cutting, machining, plasma cutting, waterjet cutting,heating, ablation, chemical removal (e.g., polymer dissolvingtechniques, metal etching techniques, etc.), laser-based techniques(sometimes referred to as laser hole formation or laser drilling),and/or other suitable material removal techniques. Openings such asopenings 38 may also be formed during the process of fabricating some orall of layer 22 (e.g., by molding openings into layer 22 as layer 22 isformed during a plastic molding process, by intertwining strands ofmaterial so that openings are formed as layer 22 is constructed, or byusing other fabrication techniques in which openings such as opening 38are formed during fabrication of layer 22 rather than by removingmaterial from layer 22 after layer 22 has been fabricated).

Patterned openings in fabric and/or other materials (see, e.g., layer 22of FIG. 3) may be used in forming illuminated regions in item 10. Asshown in FIG. 4, layer 22 may overlap an input-output component such askey 16. Key 16 may be surrounded by an illuminated region such asopening 38A that forms an illuminated trim (i.e., an illuminatedring-shaped halo that runs around the periphery of key 16). Key 16 mayalso have an illuminated region such as region 38B. Region 38B may forma symbol or other pattern. For example, illuminated region 38B may forma label for key 16 (e.g., region 38B may be patterned to form analphanumeric character 72 such as the letter “G” or other symbolassociated with the operation of the key). Regions such as regions 38Aand 38B may be formed from transparent portions of an opaque layer(e.g., perforations or larger openings in a fabric or other materialthat are filled with transparent material, air-filled openings, etc.).In some configurations, printed ink or other coating material may beprovided on layer 22 (e.g. on the outer surface of layer 22) to helpmake a label on key 16 visible to a user in the absence of illuminationthrough regions 38A and/or 38B.

Although illustrative illuminated regions 38A and 38B of FIG. 4 areassociated with an input-output device such as key 16 in keyboard 12,this is merely an example. Regions such as regions 38A and 38B may haveany suitable size and shape, may be formed on any suitable portion ofelectronic device 10, may form labels, symbols, text, decorativepatterns (e.g., trim), parts of status indicators, parts of displays,parts of buttons (e.g., buttons such as power buttons, volume buttons,sleep/wake buttons, and other buttons besides the keys in a keyboard),may be formed on surfaces of electronic device 10 that are notassociated with keys, etc. The illuminated key configuration of FIG. 4is merely an example.

In addition to pressing on desired keys 16 to supply keypress input, auser of keyboard 12 may desire to supply keyboard 12 with touch input.Keyboard 12 may, if desired, be provided with a trackpad (e.g., acapacitive touch sensor with a rectangular outline or other suitableshape that is used to gather touch input from a user). A trackpad may,as an example, be located below rows of keys in the middle of keyboard12.

Keyboard 12 may also be provided with a touch sensor that overlaps oneor more of keys 16. This touch sensor may be formed from capacitivetouch sensor electrodes or other touch sensor structures. With oneillustrative configuration, keyboard 12 may incorporate a touch sensorthat is formed from conductive strands of material in a layer of fabric(see, e.g., layer 22 of FIG. 3). The conductive strands in a fabrictouch sensor may include horizontal strands of material that overlapwith perpendicular vertical strands of material to form a grid of touchsensor electrodes that intersect at an array of intersection locations.In other arrangements, the touch sensor in keyboard 12 may be formedfrom conductive signal traces on the surface of a fabric layer or othersubstrate (e.g., a substrate formed from polymer or other suitablematerial).

The touch sensor in keyboard 12 may, as an example, overlap most or allof keys 16 and thereby may serve as a keyboard-sized integral touchsurface with which a user may supply touch input (multitouch gestures,single-finger pointer-control input for an on-screen cursor, swipes,taps, and other touch commands). To conserve space in this type ofkeyboard, it may be desirable to omit any separate trackpads (i.e.,keyboard 12 may be formed from an array of keys and a touch sensor thatextends over some or all of the keys and need not have any separatetrackpad structures). Configurations of this type may sometimes bedescribed herein as an example. In general, keyboard 12 may include anysuitable input-output devices (e.g., buttons, capacitive touch sensorsor other touch sensors, etc.).

FIG. 5 is a circuit diagram of an illustrative keyboard having a touchsensor such as touch sensor 66. As shown in FIG. 5, keyboard 12 mayinclude control circuitry 52 such as touch sensor circuitry 54 and keysensor circuitry 56. Keyboard 12 may have an array of switches 26 (FIG.3) associated with a corresponding array of keys 16.

Signal paths such as paths 48 (e.g., traces 36 on substrate 30) may beused to couple key sensor circuitry 56 to the switches 26 of keys 16.Whenever a user presses on a given one of keys 16, the switch 26 in thatkey will change state (e.g., from open to closed). Sensor circuitry 56monitors the status of all of switches 26 in keyboard 12 and, inresponse to detection of a change of switch state, generatescorresponding output signals on path 50 (e.g., signals that informcontrol circuitry in device 10 or other equipment of each detected keypress event).

Conductive lines 46 may serve as capacitive electrodes in capacitivetouch sensor 66 (e.g., a touch sensor grid) that overlaps keys 16. Anysuitable number of horizontal and vertical lines 46 may overlap each key16. For example, there may be 1-5, more than 2, more than 3, 2-4, fewerthan 10, fewer than 5, or other suitable number of horizontal lines 46overlapping each key 16 and there may be 1-5, more than 2, more than 3,2-4, fewer than 10, fewer than 5, or other suitable number of verticallines 46 overlapping each key 16. Conductive lines 46 may be formed frompatterned thin-film metal traces on layer 22, may be formed fromconductive strands of material in a layer of fabric, may be formed frompatterned traces on a layer that is separate from outer layer 22 such asa layer of polymer or other material, and/or may be formed from otherconductive structures that form capacitive touch sensor electrodes.

As shown in FIG. 5, touch sensor 66 includes touch sensor circuitry 54coupled to a set of horizontal lines 46 and a perpendicular set ofvertical lines 46. Touch sensor circuitry 54 may provide drive signals Dto one of these sets of lines 46 (i.e., horizontal lines 46 in theexample of FIG. 5) and may gather corresponding sense signals S on theother of these sets of lines 46 (i.e., vertical lines 46 in the exampleof FIG. 5). Capacitive coupling between the drive and sense lines variesin the presence of a user's finger over a drive-line-to-sense-lineintersection. As a result, touch sensor circuitry 54 can process thedrive and sense signals to determine which of the intersections of thehorizontal and vertical lines 46 are being overlapped by a user'sfinger(s) or other external objects. When touch input is detected inthis way, touch sensor circuitry 54 may provide a processor or othercontrol circuitry in device 10 or other equipment with information onthe touch input using a path such as path 58.

In a typical scenario, a user may enter text or other key press inputinto keyboard 12 by typing on keys 16. Key sensor circuitry 56 mayconvey information on the text or other input that the user is typinginto keyboard 12 over path 50. When the user desires to reposition anon-screen cursor, to make a multitouch gesture (e.g., a pinch-to-zoomgesture, a two-finger swipe, a three-finger swipe, a two-finger orthree-finger tap, etc.), to make a one-finger swipe or other gesture, orto supply keyboard 12 with other touch input, the user may move one ormore of the user's fingers across the surface of keys 16. During touchinput events such as these, touch sensor circuitry 54 may monitorcapacitance changes at the intersections of the horizontal and verticalcapacitive touch sensor electrodes (paths 46) to gather touch input dataand may supply the touch input that is gathered from the capacitivetouch sensor electrodes to control circuitry such as control circuitryin device 10 and/or control circuitry in keyboard 12 via path 54.

Touch sensor electrodes 46 may be formed from conductive strands ofmaterial in layer 22. Layer 22 may, as an example, include fabric. Thefabric may be woven, knitted, or braided and/or may include strands ofmaterial that have been intertwined using other techniques (e.g., felt).With one suitable arrangement, the fabric of layer 22 may be wovenfabric and electrodes 46 may be formed from selected warp and weftstrands in the woven fabric, as shown in FIG. 6.

FIG. 6 is a top view of an illustrative arrangement in which touchsensor 66 is incorporated into a fabric layer such as fabric 60. Fabric60 may be used as the outer layer of keyboard 12 (e.g., fabric 60 mayform layer 22 of FIG. 3) or fabric 60 may be located behind an outerlayer of keyboard 12 (e.g., fabric 60 may be located under layer 22 ofFIG. 3). As shown in FIG. 6, fabric 60 may include warp strands 62 andweft strands 64. Warp strands 62 run along a first dimension of fabric60 (e.g., the vertical dimension in the orientation of FIG. 6) and weftstrands 64 run perpendicularly along a second dimension of fabric 60(e.g., the horizontal dimension in the orientation of FIG. 6). Some ofwarp strands 62 such as strands 621 may be insulating and some ofstrands 62 such as strands 62C may be conductive and may therefore serveas the vertically extending electrodes 46 in touch sensor 66. Some ofweft strands 64 such as weft strands 641 may be insulating and some ofstrands 64 may be conductive such as strands 64C and may therefore serveas horizontally extending electrodes 46 in touch sensor 66. Woven fabric60 of FIG. 6 has a plain weave, but in general, fabric 60 may have anysuitable construction (e.g., fabric 60 may have a basket weave, may beknitted, may be braided, or may have any other suitable fabricconstruction). Plain weave fabric constructions may sometimes bedescribed herein as an example.

The strands of material in fabric 60 such as strands 62 and 64 may eachinclude one or more monofilaments (sometimes referred to as fibers ormonofilament fibers). The monofilaments may have one or more layers(e.g., a core layer alone, a core layer with an outer coating, a corelayer with an inner coating layer that is covered with an outer coatinglayer, a core layer coated with three or more additional layers, etc.).Strands of material that are formed from intertwined monofilaments maysometimes be referred to as yarns, threads, multifilament strands orfibers, etc. In general, any suitable types of strands or combination ofdifferent types of strands may be used in forming fabric 60 (e.g.,monofilaments, yarns formed from multiple monofilaments, etc.). Strandswith multiple monofilaments may have 2-200 monofilaments, 2-50monofilaments, 2-4 monofilaments, 2 monofilaments, 4 monofilaments,fewer than 10 monofilaments, 2-10 monofilaments, fewer than 6monofilaments, more than 2 monofilaments, or other suitable number ofmonofilaments.

Insulating strands may be formed from one or more dielectric materialssuch as polymers, cotton and other natural materials, etc. Conductivestrands may be formed from metal or other conductive material andoptional dielectric. For example, conductive strands may be formed fromsolid monofilament wire (e.g., copper wire), wire that is coated withone or more dielectric and/or metal layers (e.g., copper wire that iscoated with polymer), a monofilament of polymer coated with metal orother conductive material, a monofilament of polymer coated with metalthat is covered with an outer polymer coating, etc. The diameter of themonofilaments may be 5-200 microns, more than 10 microns, 20-30 microns,30-50 microns, more than 15 microns, less than 200 microns, less than100 microns, or other suitable diameter. The thickness of each of thecoatings in a monofilament may be less than 40% of the diameter of themonofilament, less than 10% of the diameter, less than 4% of thediameter, more than 0.5% of the diameter, 1-5% of the diameter, or othersuitable thickness. If desired, conductive monofilaments may beintertwined to form conductive yarn. Conductive yarn may include onlyconductive monofilaments or may include a combination of conductivemonofilaments and insulating monofilaments.

If desired, conductive strands of material and other structures infabric 60 that are associated with forming touch sensor 66 may be hiddenfrom view by covering fabric 60 with an additional layer of material.This type of arrangement is shown in FIG. 7. Fabric 60 (e.g., wovenfabric with sets of horizontal and vertical conductive strands ofmaterial that serve as capacitive touch sensor electrodes as describedin connection with FIG. 6) may be located under outer layer 22 ofkeyboard 12. Outer layer 22 may cover touch sensor 66 and may thereforehide touch sensor 66 from view. Outer layer 22 may be a layer ofplastic, a layer of fabric, and/or one or more layers of othermaterials. Outer layer 22 may be formed solely from insulating strandsand/or may be formed from strands of other materials that providekeyboard 12 with an attractive external appearance. Adhesive 106 may beused in attaching outer layer 22 to touch sensor layer 66.

Outer layer 22 may have openings 38 for allowing light 44 from lightsources 40 to pass through outer layer 22 and thereby illuminate key 16.Openings 38 may, for example, be an array of small perforations that arearranged to form a glyph or other shape as a label for key 16 (e.g.,openings 38 may be arranged in the shape of a “G” or other character asin the example of FIG. 4).

In some arrangements, signal lines 46 in touch sensor 66 may be formedfrom non-transparent materials such as metal. If care is not taken,signal lines 46 in touch sensor 66 may block some of light 44 and/or maybe visible to a user through openings 38.

To help minimize the visibility of signal lines 46 through openings 38,light-diffusing material may be located in openings 38 to help obscurelines 46 of touch sensor 66. For example, material in openings 38 maycontain metal oxide particles or other light scattering particles thatrender openings 38 translucent. With this type of arrangement, the lightdiffusing material in openings 38 may help hide signal lines 46 fromview by a user.

If desired, a separate light-diffusing layer may be used to diffuselight over touch sensor 66 and thereby help minimize the appearance ofsignal lines 46. An example of this type of arrangement is shown in FIG.8. As shown in FIG. 8, a light-diffusing layer such as diffuser 68 maybe interposed between outer layer 22 and fabric 60 of touch sensor 66.Diffuser 68 may be formed from one or more layers of polymer and mayinclude light-scattering features such as voids, inorganiclight-scattering particles, other light-scattering structures, dyes,pigments, etc. Diffuser 68 may be attached to outer layer 22 usingadhesive 106-1 and attached to fabric 60 of touch sensor 66 usingadhesive 106-2.

If desired, touch sensor 66 may be integrated into outer layer 22 ofkeyboard 12, as shown in the example of FIG. 9. With this type ofarrangement, outer layer 22 may be formed from a touch sensing fabricsuch as touch sensing fabric 60 of FIG. 6. Conductive strands in fabric60 of layer 22 may be made visually indistinct from insulating strandsin fabric 60 by matching the size and/or color of the insulating andconductive strands. For example, the diameters of the conductive strandsand insulating strands may differ by less than 50%, less than 20%, lessthan 5%, 1-10%, more than 0.1%, or other suitable amount so that theconductive strands are not visibly distinct from the insulating strands.The conductive strands may also be coated with colored polymer having acolor that matches the color of the insulating strands of material infabric 60 or may otherwise be treated so that the appearance of theconductive strands matches that of the insulating strands. As anexample, fabric 60 and/or the conducting and/or insulating strands maybe coated with a colored polymer treatment (e.g., a colored ink coatingsuch as a gray, black, or white coating, etc.). If desired, conductivestrands may be formed from conductive monofilaments that are surroundedby intertwined insulating monofilaments, thereby hiding the conductivematerial in the conductive strands from view. The insulatingmonofilaments in conductive strands with this type of arrangement mayhave the same appearance (e.g., the same color) as insulatingmonofilaments in insulating strands of material in fabric 60 (as anexample).

Incorporating touch sensor signal lines 46 into outer layer 22 ofkeyboard 12 reduces the number of layers that light 44 must pass throughto exit through openings 38, which in turn can help increase thebrightness efficiency of the keyboard.

If desired, touch sensor signal lines 46 may be formed on the surface ofouter layer 22 rather than being incorporated as threads in outer layer22. FIG. 10 is a diagram illustrating how touch sensor signal lines 46may be formed on an inner surface of outer layer 22. As shown in FIG.10, touch sensor traces 46 may be formed on a carrier layer such ascarrier layer 70. Carrier layer 70 may be a substrate formed from metal,polymer, ceramic, or other suitable material. Touch sensor signal lines46 may be formed from flexible material such as polymer (e.g., siliconeor other polymer) that has been doped with conductive filler (e.g.,particles of metal, particles of carbon nanotube material, grapheneparticles, fibrous carbon material, or other conductive particles).

Carrier substrate 70 on which touch sensor signal lines 46 are formedmay be attached to substrate 22 using adhesive 108 (e.g., epoxy,silicone, urethane, polyurethane such as thermoplastic polyurethane,acrylic, polyester, other polymers, or other suitable materials). Layer108 may also help provide a waterproof sealant on outer layer 22 toprevent moisture and other contaminants from entering keyboard 12through outer layer 22. Once attached, touch sensor signal lines 46 maybe sandwiched between layer 22 and carrier 70.

After attaching carrier layer 70 and touch sensor signal lines 46 tolayer 22, carrier layer 70 may be removed, as shown in FIG. 10. Carrier70 may be removed by ablation, cutting, machining, plasma cutting,waterjet cutting, heating, chemical removal (e.g., polymer dissolvingtechniques, metal etching techniques, etc.), and/or other suitablematerial removal techniques.

Following removal of carrier layer 70, only touch sensor signal lines 46may remain on outer layer 22. Openings 38 may be formed in layer 22prior to attaching layer 22 to carrier 70, after attaching layer 22 tocarrier 70, or after removing carrier 70 from layer 22. As in theexample of FIG. 9, integrating touch sensor signal lines 46 with outerlayer 22 helps reduce the number of layers that light needs to passthrough provide illumination for keys 16 of keyboard 12.

The example of FIG. 10 in which traces 46 are formed on carrier 70 andsubsequently attached to layer 22 is merely illustrative. If desired,traces 46 may be formed directly on layer 22 without the use of acarrier substrate.

In arrangements of the type shown in FIGS. 7, 8, and 9 where touchsensor signal lines 46 are formed from conductive strands in fabric 60(e.g., a fabric of the type shown in FIG. 6), care must be taken toensure that signal lines 46 are not visible through openings 38. FIGS.11 and 12 show illustrative arrangements in which touch sensor signallines 46 are formed in fabric 60 and are modified to minimize theirvisibility through openings 38. If desired, the arrangements of FIGS. 11and 12 may be used in fabric 60 when fabric 60 is behind outer layer 22(as in the example of FIG. 7), when fabric 60 is behind outer layer 22and behind a diffusing layer (as in the example of FIG. 8), when fabric60 is used to form outer layer 22 (as in the example of FIG. 9), and anyother suitable arrangement in which touch sensor signal lines 46 areformed from conductive strands in a layer of fabric.

In the example of FIG. 11, the conductive strands that form touch sensorsignal lines 46 (e.g., conductive strands 62C) are specifically placedin fabric 60 to avoid overlapping openings 38. In other words, adjacentsignal lines 46 may spread apart from one another to form a gap such asgap 110 that overlaps opening 38. In arrangements where fabric 60 isbehind outer layer 22 in keyboard 12 (as in the examples of FIGS. 7 and8), openings 38 may be formed in outer layer 22 and light 44 may passthrough gap 110 to reach opening 38 in outer layer 22. In arrangementswhere fabric 60 forms outer layer 22, opening 38 may be formed in fabric60. The arrangement of FIG. 11 in which only four strands in fabric 60are shown surrounding opening 38 is merely illustrative. Additionalstrands may be located between the two conductive strands 62C andbetween the two insulating strands 641 that are shown in FIG. 11. Bycircumventing opening 38 such that signal lines 46 and openings 38 arenon-overlapping, signal lines 46 may be out of a user's sight andundetectable through openings 38.

In the example of FIG. 12, signal lines 46 of touch sensor 60 are formedfrom transparent or semi-transparent materials. For example, conductivestrands 64C in fabric 60 may be formed from a fully or semi-transparentmaterial such as clear polymer 76. Polymer 76 may include conductivefiller such as conductive particles 74 (e.g., particles of metal,particles of carbon nanotube material, graphene particles, fibrouscarbon material, or other conductive particles). With this type ofarrangement, signal lines 46 that overlap openings 38 will not bevisible by a user because light 44 from light source 40 (FIG. 3) will betransmitted through the conductive strands that form signal lines 46.

If desired, touch sensor 66 need not be formed from a fabric layer. Inparticular, touch sensor signal lines 46 may be formed from traces thatare formed on a carrier substrate or that are formed directly on outerlayer 22 (as in the example of FIG. 10).

In FIG. 13, for example, touch sensor traces 46 are formed on topsurface 78T and bottom surface 78B of carrier layer 78. Carrier layer 78may be a thin film of polymer or other substrate and may besemi-transparent or fully transparent. Touch sensor signal lines 46 maybe formed from flexible conductive material such as polymer (e.g.,silicone or other polymer) that has been doped with conductive filler(e.g., particles of metal, particles of carbon nanotube material,graphene particles, fibrous carbon material, or other conductiveparticles). In one illustrative arrangement, signal lines 46 are formedfrom optically clear silicone that includes conductive particles. Signallines 46 may be fully transparent or the silicone may be light-diffusingsilicone and may only be 70-80% transparent, if desired.

Carrier layer 78 may be attached to substrate 22 using adhesive 108(e.g., epoxy, silicone, urethane, polyurethane such as thermoplasticpolyurethane, acrylic, polyester, other polymers, or other suitablematerials). Layer 108 may also help provide a waterproof sealant onouter layer 22 to prevent moisture and other contaminants from enteringkeyboard 12 through outer layer 22.

Because carrier film 78 and signal lines 46 are at least partiallytransparent, light 44 from light sources 40 can pass through openings 38without a user being able to see signal lines 46 though openings 38.

FIGS. 14 and 15 show illustrative arrangements in which non-transparentmaterials are used to form touch sensor signal lines 46 and in whichtouch sensor signal lines 46 are modified to minimize their visibilitythrough openings 38. Although the examples of FIGS. 14 and 15 showsignal lines 46 on carrier layer 78, signal lines 46 of FIGS. 14 and 15may instead be formed directly on outer layer 22 (as in the example ofFIG. 10).

In the example of FIG. 14, touch sensor signal lines 46 are specificallyplaced on substrate 78 to avoid overlapping openings 38. In other words,adjacent signal lines 46 may spread apart from one another to form a gapsuch as gap 120 that overlaps opening 38. In arrangements where signallines 46 are formed on substrate 78 that is behind outer layer 22 inkeyboard 12 (as shown in the example of 13), openings 38 may be formedin outer layer 22 and light 44 may pass through gap 120 to reach opening38 in outer layer 22. In arrangements where signal lines 46 are formeddirectly on outer layer 22 (as shown in the example of FIG. 10), opening38 may be formed in layer 22 between signal lines 46. By circumventingopening 38 such that signal lines 46 and openings 38 arenon-overlapping, signal lines 46 may be out of a user's sight andundetectable through openings 38.

In the example of FIG. 15, signal lines 46 are formed using a meshstructure such as mesh 122. Mesh 122 may be formed from metal wires or asheet of metal with openings (e.g., an array of rectangular openings oropenings of other shapes). The openings in mesh 122 may be filled withair or filler material 62 (e.g., elastomeric material, etc.). Mesh 122may be formed from wires, fine lines of a metal thin-film, or othermaterial. The lines may be sufficiently narrow to be invisible to a userof keyboard 12. Width W2 of the individual traces in mesh 122 may, forexample, be between 25 microns and 35 microns, between 20 microns and 40microns, between 10 microns and 50 microns, greater than 20 microns, orless than 20 microns. Since mesh 122 that forms signal lines 46 isundetectable by the human eye, users of keyboard 12 will be unable tosee signal lines 46 even when signal liens 46 overlap openings 38 inlayer 22.

To reduce the electrical resistance of signal lines 46, the overallwidth W1 of signal line 46 may be significantly wider than width W2 ofindividual traces that make up signal line 46. The ratio of width W1 towidth W2 may, for example, be 2:1, 10:1, 50:1, 100:1, or other suitableratio. In the example of FIG. 15, the lines of mesh 122 are oriented sothat they run at 45° relative to length L of signal line 46. In otherarrangements, the lines of mesh 122 may run parallel and perpendicularto length L of signal line 46. Other mesh orientations and layouts maybe used if desired.

FIG. 16 shows how perforations may be formed in outer layer 22 and touchsensor 66. As shown in FIG. 16, carrier layer 78 may be attached toouter layer 22. Touch sensor signal lines 46 may be formed on carrier 78and may be sandwiched between layer 22 and carrier 78. If desired,signal lines 46 may be formed directly on layer 22 (as in the example ofFIG. 10). The arrangement of FIG. 16 in which signal lines 46 are formedon carrier 78 is merely illustrative. If desired, additional layers suchas layer 80 may be attached to the lower surface of carrier 78. Layer 80may, for example, be a sealant (e.g., epoxy, polyurethane, or othersealant) or may be part of key 16 (e.g., may form part of key member24).

Following attachment of carrier 78 to layer 22, perforations 82 may beformed through outer layer 22, signal lines 46, carrier 78, and layer80. Openings 82 of FIG. 16 may be formed by stamping (punching),cutting, machining, plasma cutting, waterjet cutting, heating, ablation,chemical removal (e.g., polymer dissolving techniques, metal etchingtechniques, etc.), laser-based techniques (sometimes referred to aslaser hole formation or laser drilling), and/or other suitable materialremoval techniques. By forming openings 82 after attaching layers 22,78, and 80, openings 82 may pass completely through the entire stack,offering a clear path for light 44 from light sources 40 to exitkeyboard 12 to illuminate key 16 (FIG. 3).

FIG. 17 shows a top view of the perforated touch sensor layer of FIG.16. As shown in FIG. 16, touch sensor layer 66 may include signal lines46 formed on carrier 78. Openings 82 may be formed in touch sensor 62,thereby allowing light to pass through signal lines 46. As with openings38, openings 82 may be arranged to form an alphanumeric character orother shape that illuminates and labels key 16 for a user of keyboard12. Although openings 82 pass through signal lines 46, the resistance ofsignal lines 46 can be decreased by increasing the width of signal lines46 on layer 78.

The example of FIG. 16 in which openings 82 are formed after attachinglayers 22, 78, and 80 is merely illustrative. If desired, openings suchas openings 82 may be formed during the process of fabricating some orall layer 22, layer 78, and/or layer 80 (e.g., by molding openings intolayer 22, 78, or 80 during a plastic molding process, by intertwiningstrands of material so that openings are formed as layer 22 isconstructed, or by using other fabrication techniques in which openingssuch as opening 82 are formed during fabrication of layer 22, 78, or 80rather than by removing material from layers 22, 78, and 80 after layers22, 78, and 80 have been fabricated).

If desired, touch sensor 66 may be placed behind the light sources inkeyboard 12 to avoid blocking light and to minimize the appearance ofthe touch sensor signal lines through openings in outer layer 22. Asshown in FIG. 18, for example, touch sensor 66 may be placed behindlight sources 40 such that light sources 40 emit light away from touchsensor 66. Touch sensor 66 may, for example, be formed from a substratesuch as flexible polymer substrate 84 with conductive traces that formsignal lines 46. If desired, light sources 40 may be mounted andelectrically connected to conductive traces on substrate 84 (e.g.,substrate 84 may include a first set of traces that form touch sensorsignal lines 46 and a second set of traces that provide power andcontrol signals to light-emitting diodes 40). Because signal lines 46are located behind light sources 40, light 44 will be unobstructed bysignal lines 46 and users will be unable to see signal lines 46 throughopenings 38.

If desired, signal lines 46 may have some portions that are transparentand other portions that are non-transparent. This type of arrangement isshown in FIG. 19. As shown in FIG. 19, signal lines 46 of touch sensor66 may be incorporated into a layer such as layer 86 over key members 24of keys 16. Layer 86 may be a fabric layer located under outer layer 22(as in the example of FIGS. 7 and 8), may be a fabric layer that formsouter layer 22 (as in the example of FIG. 9), or may be a non-fabriclayer such as a layer of polymer (as in the example of FIG. 13).

Layer 86 may have rigid portions and flexible portions. For example,layer 86 may have rigid portions 86R that overlap key members 24 andflexible portions 86F in portions of layer 86 that do not overlap keymembers 24. Flexible portions 86F may allow rigid portions 86R of layer86 to move downward when a user presses down on keys 16. Rigid portions86R may be supported by key members 24 and may remain rigid and flatduring key press events.

Because portions 86R of layer 86 remain flat, the materials that formsignal lines 46 in regions 86R need not be as flexible as the materialsthat are used to form signal lines 46 in regions 86F that need to bendand flex. For example, segments of signal lines 46 in rigid portions 86Rof layer 86 may be formed from indium tin oxide or other transparentconductive material, whereas segments of signal lines 46 flexibleportions 86F of layer 86 may be formed from more flexible conductivematerials such as metal (e.g., flexible silver ink or other metal),conductive strands in fabric, or polymer with conductive filler (e.g.,flexible silicone embedded with conductive particles). Because signallines 46 are transparent in rigid portions 86R, light 44 will not beobstructed in these regions and a user will be unable to see signallines 46 through openings 38 in layer 22 (FIG. 3).

If desired, a light guide tunnel may be used to help guide light fromlight source 40 through touch sensor 66. An example, of this type ofarrangement is shown in FIG. 20. As shown in FIG. 20, light source 40may be surrounded by a wall such as light-reflective wall 88 (e.g., ametal wall or a wall that is coated with a reflective material). Wall 88may surround each light source 40 to contain light 44 and guide light 44through touch sensor layer 66. In the example of FIG. 20,light-reflective wall 88 extends from substrate 30 through touch sensor66. If desired, an optional diffuser such as diffuser 90 may be placedbetween touch sensor 66 and outer layer 22. Diffuser 90 may be formedfrom one or more layers of polymer and may include light-scatteringfeatures such as voids, inorganic light-scattering particles, otherlight-scattering structures, dyes, pigments, etc. Touch sensor signallines 46 may be specifically placed or formed in touch sensor 66 toavoid (circumvent) walls 88.

In arrangements where touch sensor 66 of FIG. 20 is formed from fabric(e.g., as in the example of FIG. 6), walls 88 may pass through touchsensor 66 by passing between adjacent strands in the fabric. Inarrangements where touch sensor 66 of FIG. 20 is formed from conductivetraces on a polymer substrate, walls 88 may pass through touch sensor 66by forming openings in the substrate and subsequently inserting walls inthe openings, or walls 88 may pass through touch sensor 66 by insertmolding the touch sensor substrate around walls 88. The presence ofwalls 88 in touch sensor 66 helps guide light through touch sensor 66while also preventing signal lines 46 from overlapping openings 38 andbecoming visible to a user.

In the example of FIG. 21, touching sensing layer 66 is interposedbetween key members 24 and light sources 40. In this type ofarrangement, touch sensing layer 66 may be a fabric touch sensor of thetype shown in FIG. 6 or may be a touch sensor formed from conductivetraces on a substrate (e.g., a flexible polymer film or othersubstrate).

Key member 24 may be formed from a light diffusing polymer and mayinclude light-scattering features such as voids, inorganiclight-scattering particles, other light-scattering structures, dyes,pigments, etc. Key members 24 may have sufficient thickness T toeffectively diffuse light 44 and obscure touch sensor signal lines 46 sothat lines 46 are not visible to viewer 94.

To form the desired alphanumeric character on keys 16, a light-maskingcoating such as coating 98 (e.g., printed ink or other coating material)may be formed on key members 24. Coating layer 98 may have openings 130that form the desired alphanumeric character or other shape. Diffusedlight 44 may travel through openings 130 to thereby form an illuminatedlabel on key 16. The light-diffusing properties of key member 24 mayhelp prevent lines 46 from being viewable through openings 130.

The foregoing is merely illustrative and various modifications can bemade by those skilled in the art without departing from the scope andspirit of the described embodiments. The foregoing embodiments may beimplemented individually or in any combination.

What is claimed is:
 1. An electronic device comprising: a substrate; anarray of keys, wherein each key in the array of keys has a switchmounted on the substrate and a movable key member that overlaps theswitch; a touch sensor layer having a first surface facing the movablekey members and a second surface facing the substrate, wherein the touchsensor layer is interposed between the movable key members and thesubstrate, the first surface is exposed between adjacent keys, and thetouch sensor layer comprises conductive traces formed on a flexiblesubstrate; and a light source mounted to the substrate, wherein thelight source illuminates the movable key members.
 2. The electronicdevice defined in claim 1 wherein the flexible substrate comprisesfabric.
 3. The electronic device defined in claim 1 wherein the touchsensor layer has an array of perforations through which light from thelight source passes.
 4. The electronic device defined in claim 3 whereinthe perforations pass though the conductive traces.
 5. The electronicdevice defined in claim 1 wherein the touch sensor layer comprises rigidregions and flexible regions.
 6. The electronic device defined in claim5, wherein the rigid regions are overlapped by the movable key membersand include transparent conductive traces and wherein the flexibleregions comprise non-transparent conductive traces.
 7. The electronicdevice defined in claim 1 wherein the touch sensor layer is configuredto receive multitouch input.
 8. The electronic device defined in claim 1wherein the movable key members are formed from light diffusingmaterial.
 9. The electronic device defined in claim 8 wherein each ofthe movable key members has a printed ink layer.
 10. A keyboard,comprising: an array of keys, wherein each key has a movable key member;an array of light sources that illuminate the array of keys; and afabric touch sensor layer that includes conductive strands woven in afabric layer that form capacitive touch sensor electrodes, wherein thefabric layer is disposed between the array of light sources and themovable key members.
 11. The keyboard defined in claim 10 wherein themovable key members comprise light diffusing material.
 12. The keyboarddefined in claim 11 wherein each of the movable key members has firstand second opposing surfaces, the first surface faces the fabric layer,and the second surface is coated with a light-masking coating.
 13. Thekeyboard defined in claim 12 wherein the light-masking coating hasopenings that are arranged to form alphanumeric characters.
 14. Thekeyboard defined in claim 13 wherein the light diffusing material of thekey members obscures the conductive strands from view.
 15. A keyboard,comprising: an array of switches; at least one key having a key cap thatis configured to press against and close a switch of the array ofswitches, wherein the key cap is formed from light diffusing materialwith light scattering particles and has a light blocking layer thatforms an alphanumeric character; a flexible capacitive touch sensorlayer with conductive traces formed on a flexible substrate overlappedby the key cap; and a light source, wherein the light source emits lightthrough the flexible capacitive touch sensor layer to illuminate the keycap and the light diffusing material with light scattering particles ofthe key cap obscures the conductive traces from view.
 16. The keyboarddefined in claim 15 wherein the flexible capacitive touch sensor layeris interposed between the switch and the key cap.
 17. The keyboarddefined in claim 16 wherein the flexible capacitive touch sensor layercomprises a fabric with conductive signal lines.
 18. The keyboarddefined in claim 15 wherein the light blocking layer comprises alight-masking coating.